In conventional practice, a medical application tube has been used to drain the drainage accumulated in the wound site of a patient. There is a medical application tube comprised by a silicone mold including a basal end side portion having a cylindrical shape and a tip end side portion to be indwelled at the wound site of the patient which is formed into a plurality of flow pathways which are sectioned by a central axis therebetween. Further, to this tip end side portion of the medical application tube, slits are formed by notched the outer peripheral side portions of wall portions forming flow pathways along the axial direction, respectively. By providing these slits, the size of the opening of the medical application tube can be increased to effectively suction the drainage (for example Patent Literature 1: Japanese Patent Examined Publication No. H02-17185).
The cross sectional shape of the tip end side portion of this medical application tube (wound site drain catheter) has four flow paths formed by coupling each tip end portion of a cross piece to the ring shaped inner surface and each of four flow paths are communicated with the outside by forming slits by notching the portions each corresponding to between pieces of the ring. Alternatively, three flow paths are formed by coupling each tip end portion of three pieces extended from the center of the ring in three directions to the ring shaped inner surface and each of three flow paths are communicated with the outside by forming slits formed by notching the portions each corresponding to between pieces of the ring.
Further, when the conventional medical application tube as described above is produced, for example, the tube in which the cross sectional shape of the tip end side portion of this medical application tube (wound site drain catheter) has four flow paths formed by coupling each tip end portion of a cross piece to the ring shaped inner surface is formed by extrusion molding and slits are formed by notching formed by processing the portions each corresponding to between pieces of the ring to form the tube for medical tube or it is carried out to directly extrusion molding the medical application tube having slits.
However, in the method for producing the conventional medical application tube, when the slits are formed by processing, there is a problem in that the production cost is increased. While when the medical application tube is once formed into the final shape thereof by extrusion molding and the molding material thereof is soft resin, since, in general, the sliding between this material and the metallic sleeve of the extrusion mold is not good, it is difficult for form the tube by, for example, vacuum sizing. Moreover, even though the material is soft, when it is silicone resin (non thermoplastic resin), the viscosity thereof is high whereby the shape near the shape of mol space of the extrusion mold can easily be molded, while when the molding material comprised by a soft thermoplastic resin such as soft polyurethane or soft polyvinyl chloride is used, the molding by the conventional extrusion molding, same as in the case of silicone resin, can not be carried out.
The invention has been made in the light of these problems and the object of the invention is to provide a mold for an extrusion molding with which a molding a medical application tube having a complex configuration by using a soft thermoplastic resin and an extrusion molding method can be accomplished.